Software for Programming Microbes

Genetically modified microbes could perform many useful jobs, from making biofuels and drugs, to cleaning up toxic waste. But designing the complex biochemical pathways inside such microbes is a time-consuming process of trial and error.

Christopher Voigt, an associate professor at the University of California, San Francisco, hopes to change that with software that automates the creation of "genetic circuits" in microbes. These circuits are the pathways of genes, proteins, and other biomolecules that the cells use to perform a particular task, such as breaking down sugar and turning it into fuel. Voigt and colleagues have so far made basic circuit components in E. coli. They are working with the large California biotechnology company Life Technologies to develop software that would let bioengineers design complete genetic circuits more easily.

Designing a microbe for a particular task would then be much like writing a new computer program, says Voigt. Just as programmers do not have to think about how electrons move through the gates in an integrated circuit, he says, biological engineers may eventually be able to design circuits for genes, proteins, and other biomolecules at a level of abstraction. "If we apply computational processes to things that bacteria can already do, we can get complete control over making spider silk, or drugs, or other chemicals," he says.

Certain types of circuits could, for instance, help regulate the activity of bacteria that produce biofuels. Instead of outside controls, internal circuits could maintain the chemical levels and other conditions needed to keep bacteria producing at high yields. "We're trying to make the cell understand where it is and what it should be doing based on its understanding of the world," says Voigt. Trying to design such a control circuit without the help of a computer would take a lot of trial and error.